Note sur la présence d'une forme stérile d'Oxalis pes-caprae L. au Maroc.

About a presence of sterile form of Oxalis pes-caprae L. in MoroccoNote sur la présence d'une forme stérile d'Oxalis pes-caprae L. au MarocNote sur la présence d'une forme stérile d'Oxalis pes-caprae L. au Maro

Flore ("Pteridophyta" et "Spermatophyta") des zones humides du Maroc Méditérranéen: Inventaire et écologie

Despite the interest that one wears increasingly to wetlands through the world, few studies have been devoted to Moroccan wetland flora. After having prospected 45 sites, we have evaluated the specific diversity of wetland flora from 70 floristic inventories. Among 389 recognised species in this study, 175 are wetland species. Rare species or newly quoted have been underlined. On the other hand, the observed plant groupings have been classified according to the physiognomy and the specific composition. A particular attention has been devoted to the discussion of the main ecological factors affecting wetland plant groupings namely : the submersion, the salinity, the domestic organic loading, the local climate and the anthropic perturbations. Thereby, we have ranked dominant species in some ecological groups.Malgré l'intéret qu' on porte de plus en plus aux zones humides á travers le monde, peu d' etudes ont été consacrées á la flore hygrophile marocaine. Aprés avoir prospecté 45 stations, on a évalué la diversité spécifique des hygrophytes du Maroc méditerranéen á partir de 70 relevés floristiques. Sur les 389 espéces reconnues dans cette etude, 175 especes sont caractéristiques des zones humides. Les espéces rares ou nouvellement citées ont été soulignées. D'autre part, les phytocenoses observées ant été classées en fonction de la physionomie et de la composition spécifique. Une attention particuliere a été consacrée á la discussion des principaux facteurs écologiques influant sur les groupements hygrophiles á savoir : la submersion, la salinité, la charge organique domestique, le mésoclimat et les travaux d'aménagement. Ainsi, on a pu regrouper les espéces dominantes en classes écologiques

Tolérance et accumulation du cuivre et du chrome chez deux espèces de lentilles d’eau : Lemna minor L. et Lemna gibba L.

Certains procédés d’épuration extensive des eaux usées utilisent les lentilles d’eau. Les rejets des eaux usées sont de plus en plus sujets à des pollutions de natures diverses, notamment les métaux lourds. Dans ce travail, on procède à une évaluation comparée de la tolérance et de l’accumulation de deux métaux lourds, le cuivre et le chrome, par deux espèces de lentilles d’eau Lemna minor et Lemna gibba. Bien que sous climat de type méditerranéen, L. gibba soit plus utilisée que L. minor, les données disponibles dans la littérature concernent plutôt L. minor. L’évaluation des paramètres toxicologiques montre chez L. gibba une tolérance nettement supérieure aux effets toxiques des deux métaux expérimentés. Le chrome est moins toxique que le cuivre et s’accumule à des taux supérieurs à ceux du cuivre dans les tissus des plantes. Pour les deux métaux, l’accumulation est plus importante chez L. minor. Cependant, on pense que L. gibba serait plus indiquée dans des applications en phytoremédiation que L. minor, vu sa tolérance et sa productivité en biomasse. Les potentialités de ces deux espèces pour des applications de ce type se justifient par des taux d’accumulation fort élevés, spécialement pour le chrome où ils dépassent largement les 1000 µg g‑1 de poids sec. En effet, les concentrations des plantes en Cr obtenues dans ce travail atteignent 2140 µg g‑1 chez L. minor et 1710 µg g‑1 chez L. gibba. Ces performances montrent un potentiel fort intéressant en comparaison à d’autres macrophytes comme la jacinthe d’eau par exemple.Natural wastewater treatment technologies are common practice in many regions of the world. Although these technologies are normally meant for domestic wastewater treatment, they can have broader applications such as the treatment of water contaminated by heavy metals.Among various existing technologies, systems that use duckweed are exploited for wastewater treatment in various regions of the world. In Morocco, this type of system has been tested on an experimental scale and a pilot scale. The most common duckweeds species are Lemna minor L. and Lemna gibba L. L. gibba is used in Mediterranean climates more often than L. minor, but literature data on the tolerance and accumulation of heavy metals are mostly available for L. minor.In the current study, we compared the tolerance and accumulation of two heavy metals, copper (Cu) and chromium (Cr), for these two duckweed species. Thus, this study compares the potential of these two duckweed species to be used as a method of decontaminanting Cu‑ and Cr‑contaminated water. The experimental design used hydroponic crops of the two species. Forty fronds of each species were sown in plastic pots containing 100 mL of White nutritive solution with a pH adjusted to 6.8. As experimental treatments, we used exposures corresponding to the following concentrations: 0.5; 1; 2; 3; 4; 5 mg Cu/L and 3; 5; 10; 20; 30; 35 mg Cr/L. Each treatment was repeated five times. In order to compensate for water loss by evapotranspiration, we added 15 mL of the corresponding solution to each treatment daily.Generally, the results obtained confirm that Cu is more toxic than Cr and that the two species of duckweed have different tolerance levels; L. minor is more sensitive than L. gibba for both metals. For Cu, we observed a highly significant inhibition of growth in response to the gradient of Cu concentrations used, the growth of L. minor being more affected than that of L. gibba. For example, the time required for L. minor colonies to double was more than four days for 1 mg Cu/L, whereas for L. gibba this was observed only at 3 mg Cu/L. The toxicological parameters reflect this observation as L. minor had both a lower NOEC (No Observed Effect Concentration) and a lower IC50 (50% Inhibition Concentration) than those reported for L. gibba. Comparatively, these results show a higher tolerance of Cu contamination for L. gibba.For Cr, L. minor was more sensitive than L. gibba, but in much less marked way than for Cu. Indeed, the time required to double the colony size and the NOEC value were similar for the two species, whereas the IC50 of L. minor was lower than that of L. gibba. The comparison of the rate of inhibition confirms a slightly greater sensitivity of L. minor to Cr exposure.The Cu and Cr concentrations in the biomass increased with the concentration of metal; the highest contents were observed in the treatments with the highest concentrations used: 5 mg Cu/L and 10 mg Cr/L. However, the BCF (Bioconcentration Factor) decreased with the concentration of the treatment; the highest values were observed for the treatments with the lowest concentrations (1 mg Cu/l and 3 mg Cr/L). With respect to possible applications in phytoremediation, the potential use of these two species would be more efficient for low levels of contamination.The two species accumulate the two metals at different rates; the accumulation of Cr is greater than that of Cu and L. minor shows higher rates of accumulation. Copper concentrations of approximately 800 µg/g were obtained in L. minor exposed to 5 mg Cu/L. For Cr, concentrations were approximately 2140 µg/g obtained in L. minor exposed to 10 mg Cr/L. For L. gibba, the maximum concentrations obtained were 745 µg/g and 1710 µg/g respectively for the treatments of 5 mg Cu/L and 10 mg Cr/L. Similarly, the BCF estimated at L. minor was higher than that of L. gibba.Compared with other macrophyte species, the duckweeds show a very interesting potential for metal accumulation. Indeed, for Cu, accumulation was definitely higher than that for other species such as Eichhornia crassipes and Polygonum hydropiperoides. The BCF obtained was higher than those observed for species of Typha and Spartina. These results confirm that L. minor and L. gibba could be good Cu accumulating species compared to other macrophytes. For Cr, other species of macrophytes accumulate this metal to a greater or lesser extent: E. crassipes (slower rate than that of the duckweeds), Nymphea alba (similar rate to that of the duckweeds) or Azolla pinnata (higher rate than the duckweeds). The Cr contents accumulated by the two duckweed species would justify their classification as hyperaccumulator species.With respect to tolerance, accumulation potential and biomass productivity, L. gibba shows potential as a species that could be used in phytoremediation and in particular the rhizofiltration of wastewater contaminated by Cu and Cr

Première Caractérisation Pomologique Des Variétés Locales De L’olivier (Olea Europaea L.) Des Oliveraies Traditionnelles Des Agroécosystèmes Des Montagnes Du Nord-Ouest DuMaroc

Les oliveraies traditionnelles du nord-ouest du Maroc se différencient par une diversité variétale relativement importante contrairement au paysage oléicole marocain dominé par une seule variété, la Picholine marocaine. En effet, les pratiques traditionnelles locales à travers le maintien des vergers poly-variétaux ont permis la conservation de variétés locales rares et sousutilisées. Dans cette étude nous avons réalisé l’échantillonnage selon un dispositif équilibré (10 arbres par variété et 30 olives par arbre) des 6 variétés locales dénommées et reconnues par les agriculteurs (Zeitoun, Bouchouk, Hamrani, Kortbi, Asemlal, Semlal), d’un écotype d’oléastre forme spontanée de l’olivier et deux variétés sélectionnées utilisées par les agriculteurs (Haouzia et Menara). L’étude pomologique s’est appuyée sur l’utilisation de 15 caractères quantitatifs décrivant la taille et la forme des olives et des noyaux ainsi qu’une estimation indirecte de la teneur en huile. Les résultats obtenus montrent que les variétés étudiées se différencient le long d’un gradient de taille et du potentiel productif, les caractères relatifs à la forme jouent un rôle secondaire dans cette différentiation. Ainsi, les variétés à petites olives (Oléastre et Asemlal) se différencient nettement des variétés à grosses olives (Meslal) et des variétés à olives de tailles intermédiaires (Zeitoun, Hamrani, Bouchouk, Kortbi, Haouzia et Menara). Les variétés de tailles intermédiaires se différencient plutôt par les caractères relatifs à la forme. La variété Kortbi se différencie nettement en s’opposant aux variétés sélectionnées Haouzia et Menara. Les variétés Zeitoun, Bouchouk et Hamrani se chevauchent largement. Unlike the Moroccan olive oil landscape characterized by the dominance of a single variety, the Moroccan Picholine, the traditional olive groves of north-west Morocco are distinguished by a relatively large variety diversity. Indeed, local traditional practices through the maintenance of polyvarietal orchards have allowed the conservation of rare and underused local varieties. In this study we carried out the sampling according to a balanced design (10 trees per variety and 30 olives per tree) of the 6 local varieties named and recognized by the farmers (Zeitoun, Bouchouk, Hamrani, Kortbi, Asemlal, Semlal), an oleaster spontaneous form of the olive tree and two selected varieties used by farmers (Haouzia and Menara). The pomological study was based on the use of 15 quantitative characters describing the size and shape of the olives and endocarp, as well as an indirect estimate of the oil content. The results obtained show that the varieties studied are differentiated along a size gradient and the productive potential, the characters relating to the form play a secondary role in this differentiation. The varieties with small olives (Oleaster and Asemlal) are clearly distinct from the varieties with large olives (Meslal) and the olive varieties of intermediate sizes (Zeitoun, Hamrani, Bouchouk, Kortbi, Haouzia and Menara). The varieties of intermediate sizes are rather differentiated by the characters relating to the form. The Kortbi variety is clearly differentiated by opposing the selected Haouzia and Menara varieties. The varieties Zeitoun, Bouchouk and Hamrani largely overlap

Traditional agroecosystems as conservatories and incubators of cultivated plant varietal diversity: the case of fig (Ficus carica L.) in Morocco

<p>Abstract</p> <p>Background</p> <p>Traditional agroecosystems are known to host both large crop species diversity and high within crop genetic diversity. In a context of global change, this diversity may be needed to feed the world. Are these agroecosystems museums (i.e. large core collections) or cradles of diversity? We investigated this question for a clonally propagated plant, fig (<it>Ficus carica</it>), within its native range, in Morocco, but as far away as possible from supposed centers of domestication.</p> <p>Results</p> <p>Fig varieties were locally numerous. They were found to be mainly highly local and corresponded to clones propagated vegetatively. Nevertheless these clones were often sufficiently old to have accumulated somatic mutations for selected traits (fig skin color) and at neutral loci (microsatellite markers). Further the pattern of spatial genetic structure was similar to the pattern expected in natural population for a mutation/drift/migration model at equilibrium, with homogeneous levels of local genetic diversity throughout Moroccan traditional agroecosystems.</p> <p>Conclusions</p> <p>We conclude that traditional agroecosystems constitue active incubators of varietal diversity even for clonally propagated crop species, and even when varieties correspond to clones that are often old. As only female fig is cultivated, wild fig and cultivated fig probably constitute a single evolutionary unit within these traditional agroecosystems. Core collections, however useful, are museums and hence cannot serve the same functions as traditional agroecosystems.</p

Structure et diversité de la strate arbustive des forêts de la Péninsule Tingitane (Maroc).

RÉSUMÉ. Structure et diversité de la strate arbustive des forêts de la Péninsule Tingitane (Maroc). Cette étude concerne les communautés végétales arbustives des massifs forestiers sur substrat gréseux couvrant la Péninsule Tingitane au nord ouest du Maroc. La structure et la diversité de ces communautés ont été étudiées sur la base de 98 relevés représentatifs. Les subéraies (Quercus suber) sont les formations forestières naturelles les plus représentatives et les plus diversifiées de l´aire d´étude. L´altitude s’est révélée être un facteur écologique très discriminant, en séparant clairement les communautés arbustives des forêts des hautes montagnes. Au niveau des zones de basses altitudes, la fertilité, l´acidité et la perturbation anthropique jouent un rôle déterminant dans la distribution des communautés végétales arbustives. Cette distribution semble exprimer la dynamique de la végétation selon un gradient de conservation-perturbation. En conclusion, l´étude souligne l´intérêt remarquable que présentent les forêts du nord du Maroc, du point de vue de leurs significations écologiques, biogéographiques et évolutives.Mots clés. Péninsule tingitane, diversité, écologie, strate arbustive, substrat gréseux.RESUMEN. Estructura y diversidad del estrato arbustivo de bosques de la Península Tingitana (Marruecos). Se estudian las comunidades arbustivas de los bosques que se presentan sobre la formación de arenisca de la Península Tingitana en el noroeste de Marruecos. Se analiza la estructura y diversidad de estas comunidades en base a 98 muestras representativas. Los alcornocales (Quercussuber) son las formaciones forestales más representativas y más diversificadas en el área de estudio. La altitud es el principal factor ecológico, separando nítidamente las comunidades arbustivas de los bosques de zonas altas, según el análisis de correspondencia canónica (CCA). Por otro lado, en los bosques de zonas bajas, la distribución de las comunidades arbustivas viene determinada por el grado de fertilidad y acidez del suelo, y por la perturbación antrópica. Esta distribución parece reflejar la dinámica de la vegetación según un gradiente de conservación – perturbación. Por último, el estudio  Cellellama la atención sobre el gran interés que presentan los bosques del norte de Marruecos, desde el punto de vista ecológico, biogeográfico y evolutivo.Palabras clave. Península Tingitana, diversidad, ecología, estrato arbustivo, areniscas

Evolution Du Couvert Végétal Naturel Au Niveau Des Massifs Forestiers De Mallalyine Et Taghramt (Rif Occidental Du Maroc)

This work presents the results of a cartographic study of the spatiotemporal evolution of vegetation cover in the forest areas of Mallalyine and Taghramt in the western Rif. It is based on a field survey and the photointerpretation of aerial photographs taken in 1986 and Google Earth images from 2013 (a period of twenty-seven years). Our study reports on the current state of degradation of the vegetation cover in the forests of Mallalyine and Taghramt. We have produced two land use maps showing how high and low formations as well as scrub have regressed by 62, 70 and 49 percent, respectively, between 1986 and 2013, while non-forested land and reforestation increased respectively by 26.3 and 1.53 percent relative to the area covered in 1986. The main factors contributing to the decline of vegetation cover are: deforestation (35 offenses registered every year with a degraded area of about 15 ha / year), clearing (27 offenses per year with an European Scientific Journal August 2018 edition Vol.14, No.24 ISSN: 1857 – 7881 (Print) e - ISSN 1857- 7431 20 affected area of about 20 ha / year), overgrazing (10 offenses of illegal grazing per year with a degraded area of about 12 ha / year), forest fires (4 to 5 fires per year with a degraded area of about 50 ha / year). In addition to these factors, we find increasing water scarcity